str1 = "Hello world"
str2 = "Hello world"
str3 = '''   
world'''
print(str1)
print(str2)
print(str3)
print('hel\'lo world')#\转义符
print('123---{0}---{1}---{2}'.format(4, 5, 6))
str1 = 'hello'
print(f'123---{str1}')
#文本进度条"
for i in range(0,101,2):
    print("==========开始下载==========")
    if i==100:
        print("==========下载完成==========")
    else:
        str4 = "*" *(i//2) + "."*((100-i)//2)
        print(f'{i}%[{str4}]')
      # print(f'{i}%','[',"*" *(i//2),"."*((100-i)//2),']')
